The City of Hope (COH) is a National Cancer Institute-designated Comprehensive Cancer Center with multiple Cancer Center funded core services. The Analytical Cytometry Core (ACC) at COH supports basic research and pre-clinical studies of cell populations through the provision of leading-edge analytical and preparative cytometry equipment and experienced operators. Cytometry instrumentation in this shared resource currently includes an analytical flow cytometer and a high speed fluorescence activated cell sorter (MoFlo, Dako/Cytomation, Fort Collins, CO). Requests for analysis and sort time from institutional program members in Hematology &Hematopoietic Cell Transplantation, Cancer Immunotherapeutics, and Developmental &Stem Cell biology exceeds the capacity of the current facility both in terms of access to and sophistication of the instrumentation. The addition of a state-of-the-art high speed cell sorter (inFlux, Cytopeia, Seattle, WA) is proposed in support of those investigators with demonstrable need and peer reviewed funding. The long term objective of this proposal is to obtain, install, qualify and operate a state-of-the-art cell sorter to increase available hours for cell sorting and providing up to 24 parameter (7-laser) analysis and high speed (50K events/sec) sort capability to qualified investigators. Institutional support will include renovation of existing space to accommodate new equipment and funds for a dedicated operator. All instrumentation will be maintained according to ACC quality assurance policies regarding testing, calibration and preventive maintenance to ensure performance at manufacturer's specification at all times. Priority access will be for investigators with peer-reviewed funding named in this application, with unused capacity made available to other Cancer Center members and then to non- members. The importance of this proposal and its contribution to public health lie in the continual provision of state-of-the-art equipment for basic and translational studies aimed at developing new and more effective cancer and anti-viral therapeutics.